Buggy code:
} employee = employees . get ( id ) ; log . trace ( ( "Employee=" + employee ) ) ; em . remove ( employee ) ; break ; case Refresh : id = 1 ; if ( ( args . length ) > 1 ) { id = ( ( Integer ) ( args [ 1 ] ) ) ; } employee = employees . get ( id ) ; log . trace ( ( "Employee(before)=" + employee ) ) ; em . refresh ( employee ) ; log . trace ( ( "Employee(after)<seq2seq4repair_space>=" + employee ) ) ; break ; case RefreshWithLock : id = 1 ; if ( ( args [ 1 ] ) != null ) { id = ( ( Integer ) ( args [ 1 ] ) ) ; } lockMode = LockModeType . NONE ; if ( ( args [ 2 ] ) != null ) { lockMode = ( ( LockModeType ) ( args [ 2 ] ) ) ; } employee = employees . get ( id ) ; log . trace ( ( "Employee(before)=" + employee ) ) ; Map < String , Object > refreshProps = buildPropsMap ( args , 3 ) ; if ( refreshProps != null ) { em . refresh ( employee , lockMode , refreshProps ) ; } else { em . refresh ( employee , lockMode ) ; } log . trace ( ( "Employee(after)<seq2seq4repair_space>=" + employee ) ) ; break ; case RefreshObject : em . refresh ( args [ 1 ] , ( ( LockModeType ) ( args [ 2 ] ) ) ) ; break ; case Lock : id = 1 ; if ( ( args [ 1 ] ) != null ) { id = ( ( Integer ) ( args [ 1 ] ) ) ; } lockMode = LockModeType . NONE ; if ( ( args [ 2 ] ) != null ) { lockMode = ( ( LockModeType ) ( args [ 2 ] ) ) ; } employee = employees . get ( id ) ; log . trace ( ( "Employee=" + employee ) ) ; Map < String , Object > lockProps = buildPropsMap ( args , 3 ) ; if ( lockProps != null ) { em . lock ( employee , lockMode , lockProps ) ; } else { em . lock ( employee , lockMode ) ; } break ; case LockObject : em . lock ( args [ 1 ] , ( ( LockModeType ) ( args [ 2 ] ) ) ) ; break ; case UpdateEmployee : id = 1 ; if ( ( args . length ) > 1 ) { id = ( ( Integer ) ( args [ 1 ] ) ) ; } employee = employees . get ( id ) ; log . trace ( ( "Employee<seq2seq4repair_space>(before):" + employee ) ) ; String newFirstName = "Unknown" ; if ( ( args . length ) > 2 ) { newFirstName = ( ( String ) ( args [ 2 ] ) ) ; } else { newFirstName = new Date ( ) . toString ( ) ; } employee . setFirstName ( newFirstName ) ; log . trace ( ( "Employee<seq2seq4repair_space>(after)<seq2seq4repair_space>:" + employee ) ) ; break ; case Detach : id = 1 ; if ( ( args [ 1 ] ) != null ) { id = ( ( Integer ) ( args [ 1 ] ) ) ; } employee = employees . get ( id ) ; log . trace ( ( "Employee<seq2seq4repair_space>(before)<seq2seq4repair_space>:" + employee ) ) ; <START_BUG> LockEmployee detEmployee = ( ( OpenJPAEntityManager ) ( em . getDelegate ( ) ) ) . detach ( employee ) ; <END_BUG> employees . put ( ( ( Integer ) ( args [ 2 ] ) ) , detEmployee ) ; log . trace ( ( "Employee<seq2seq4repair_space>(after)<seq2seq4repair_space>:" + detEmployee ) ) ; break ; case StartTx : em . getTransaction ( ) . begin ( ) ; break ; case CommitTx : em . getTransaction ( ) . commit ( ) ; break ; case RollbackTx : em . getTransaction ( ) . rollback ( ) ; break ; case NewThread : int childToRun = ( ( Integer ) ( args [ 1 ] ) ) ; SequencedActionsTest . TestThread t1 = new SequencedActionsTest . TestThread ( childToRun , actions ) ; threads . add ( t1 ) ; break ; case StartThread : threads . get ( ( ( Integer ) ( args [ 1 ] ) ) ) . start ( ) ; break ; case Notify : int notifyThreadid = 0 ; if ( ( ( args . length ) > 1 ) && ( ( args [ 1 ] ) != null ) ) { notifyThreadid = ( ( Integer ) ( args [ 1 ] ) ) ; } if ( ( args . length ) > 2 ) { Thread . sleep ( ( ( Integer ) ( args [ 2 ] ) ) ) ; } if ( notifyThreadid == 0 ) { notifyParent ( ) ; } else { threads . get ( notifyThreadid ) . notifyThread ( ) ; } break ; case Wait : int waitThreadid = threadToRun ; if ( ( ( args . length ) > 1 ) && ( ( args [ 1 ] ) != null ) ) { waitThreadid = ( ( Integer ) ( args [ 1 ] ) ) ; } int waitTime = 5000 ; if ( ( ( args . length ) > 2 ) && ( ( args [ 2 ] ) != null ) ) { waitTime = ( ( Integer ) ( args [ 2 ] ) ) ; } if ( waitThreadid != 0 ) { thisThread . wait ( waitTime ) ;

Fix:
LockEmployee detEmployee = ( ( OpenJPAEntityManager ) ( em . getDelegate ( ) ) ) . detachCopy ( employee ) ;